Mo-ZrO_2金属陶瓷耐蚀性能与组成的关系

用金属Mo粉和ZrO2粉,在1600℃下烧结制备了Mo摩尔百分数分别为60%、50%和40%的3种Mo-ZrO2金属陶瓷试样.在Ar保护气氛下,分别用1550℃的IF钢和CaO-Al2O3-MgO预熔渣将3种试样侵蚀2h.用SEM分别比较了试样在钢液和熔渣侵蚀后断口形貌的变化,用EDS分析了钢液侵蚀后试样的边缘处、距边缘0.25,0.5和1mm处的元素组成.结果表明,Mo含量为40%的试样耐钢液侵蚀能力最强,随着Mo含量的增多,金属陶瓷耐钢液侵蚀性能逐渐减弱;Mo含量为60%的试样耐熔渣侵蚀性能较好,随着Mo含量的减少,金属陶瓷耐熔渣侵蚀性能逐渐减弱.     

A12O3-W金属陶瓷用于金属熔体温度测量可行性研究

采用高纯氧化铝和不同含量金属钨制成的Al2O3-W金属陶瓷作为热电偶两极,直接浸入金属熔体中进行连续测温实验.结果表明:该金属陶瓷热电偶输出的热电动势较大,在金属熔化温度范围内其热电动势与温度的线性关系明显.金属陶瓷具有良好的耐热态金属及熔渣侵蚀性能,可实现对高温熔体温度的连续测量.     

耐磨工程和切削钢用氧化锆增韧氧化铝

叙述了用溶液蒸发分解来合成Y2O3基部分稳定氧化锆,以及用湿化学沉淀法获得α-Al2O3和用粉末冶金工艺制造氧化锆增韧氧化铝陶瓷的方法。对用氧化锆增韧氧化铝烧成的制品用作切削工具嵌刃和在其它耐磨工程性能方面进行了特性分析。在实验中切削钢时观察到应力引起的氧化锆增韧氧化铝陶瓷的韧性变化,调查了月牙洼和侧面磨损对切削钢的影响。硬度和断裂韧性与提高切削性能(钢切削效率)和其它耐磨工程的使用都有关联。     

MnZn铁氧体承烧板性能的比较

部分稳定氧化锆材料(PSZ)以其优良的高温化学稳定性和抗热震性而成为MnZn铁氧体承烧板的首选材料。PSZ材料在1100℃以上反复使用会发生反稳定化现象。本文对比了钙稳定氧化锆(Ca-PSZ)和钇稳定氧化锆(Y-PSZ)反稳定化现象,及反稳定化现象对材料物理性能的影响。结果表明:Y-PSZ晶相更为稳定,性能也更为稳定,更适合用于MnZn铁氧体的承烧。     

高铬砖与煤渣侵蚀反应的初探

使用扫描电镜和能谱仪研究了高铬砖(Cr2O3-Al2O3-ZrO2)的侵蚀反应,结果呈现出两种形式:一是形成含有部分脱锆层、再生单斜氧化锆层、再生单斜氧化锆和锆英石共存层、锆英石层;二是形成部分脱锆层和含有单斜氧化锆的渗透层。两种类型的侵蚀反应是由煤渣成分不同引起渗透层中m(CaO)/m(SiO2)比值的差异造成的:当渗透层中m(CaO)/m(SiO2)0.22时,首先在高铬砖内部由渣中SiO2与m-ZrO2形成锆英石层,再随着渗透层中m(CaO)/m(SiO2)比值的增加,形成再生单斜氧化锆和锆英石共存层、再生单斜氧化锆层和部分脱锆层;当渗透层中m(CaO)/m(SiO2)0.27时,易形成部分脱锆层和含有单斜氧化锆的渗透层。     

铝电解用梯度网状惰性Ag/NiFe_2O_4阳极的制备及性能

为了提高铝电解用金属陶瓷惰性阳极材料的综合性能,制备了圆柱形梯度网状结构的Ag/NiFe2O4阳极材料。采用叠层法实现梯度结构,从芯部到外部金属Ag含量依次减少,最外层为纯陶瓷NiFe2O4;采用原料粒度级配实现金属陶瓷层中金属相的网状分布。结果发现:对于一定规格的样品,通过设计合适的层数、各层的成分和粒度级配可成功制得梯度网状结构的阳极。对芯部含30%(质量分数)Ag的样品进行导电性、抗腐蚀性的测试发现,梯度网状结构阳极的导电性优于含等量金属Ag的均匀结构阳极。阳极最外层为纯陶瓷,表现出很好的抗腐蚀性。梯度网状结构将梯度结构的优点和网状结构的优点相结合,能够有效提高阳极材料的综合性能。     

YSZ/MgAl_2O_4复合粉末的合成及其材料的烧成活化能

采用共沉淀法在1100℃制备了70%(体积分数,下同)氧化钇稳定氧化锆[xY2O3+(1-x)ZrO2,x=0.02,0.03,0.04,in mole,yttria stabilized zirconia,YSZ]-30%镁铝尖晶石(MgAl2O4)复合粉体,2种原始粉料的配料各为70%和30%,并在1200～1500℃常压烧成制备了陶瓷材料。结果表明:在制得的所有粉末中,未发现单斜相ZrO2;2YSZ(0.02Y2O3+0.98ZrO2,摩尔分数,下同)/MgAl2O4和3YSZ/MgAl2O4这2种粉体中的ZrO2为四方相多晶氧化锆;而4YSZ/MgAl2O4粉末中的ZrO2相为全稳定立方氧化锆。对于1500℃烧结制备的陶瓷材料,2YSZ/MgAl2O4块体中的ZrO2相为部分稳定氧化锆;而3YSZ/MgAl2O4和4YSZ/MgAl2O4块体中的ZrO2相为全稳定氧化锆。(2～4)YSZ/MgAl2O4复相陶瓷的活化能为(623±80)kJ/mol。     

太阳能热发电用氧化铝-碳化硅-氧化锆储热陶瓷的制备及表征

以α-Al2O3、部分稳定氧化锆(5.2%Y2O3,质量分数)和碳化硅为原料,采用无压烧成技术制备了太阳能热发电用 Al2O3–SiC–ZrO2(ASZ)储热陶瓷,研究了碳化硅和氧化锆添加量对 ASZ 储热陶瓷样品结构与性能的影响。结果表明：随着碳化硅添加量的增加,样品的力学性能、抗热震性和热物理性能均有提高;添加氧化锆可提高样品的力学性能和抗热震性能;经1280℃烧成的碳化硅添加量为50%、部分稳定氧化锆添加量为5%的样品的显气孔率、吸水率、体积密度和抗折强度分别为24.88%、10.44%、2.38 g/cm3和66.20 MPa;样品的比热容、导热系数和储热密度(600℃时)分别为1.05 kJ/(kg·K),2.26 W/(m·K)和916.91 kJ/kg。热震试验30次(室温～800℃)样品无裂纹,强度增长率为27.89%。     

氧化锆陶瓷子弹的高速冲击动态性能

为对比陶瓷子弹与普通钢弹的侵彻能力,以3%(摩尔分数)氧化钇稳定的氧化锆粉体为原料,通过凝胶注模成型工艺得到了尺寸、质量均符合要求的陶瓷子弹,将ZrO2陶瓷子弹和钢弹在相同条件下分别对3种典型的靶板进行了侵彻深度试验。结果表明:在侵彻Al2O3陶瓷/Kevlar纤维材料复合靶时,ZrO2陶瓷子弹冲击形成的破碎陶瓷锥半径为钢弹的1.5倍;在侵彻均质装甲钢时,ZrO2陶瓷子弹的穿孔面积比钢弹增大了34.7%;只有ZrO2陶瓷子弹可以穿透Al2O3陶瓷/钢板复合靶。ZrO2陶瓷子弹对靶板的侵彻效果优于钢弹,ZrO2陶瓷在穿甲弹丸设计上有较好的应用前景。     

稀土La_2O_3对重力条件下复合陶瓷钢管陶瓷内衬组织的影响

根据铝热反应,研究了复合陶瓷钢管重力条件下制备含SiO2系列陶瓷内衬,以及含稀土La2O3加SiO2系列陶瓷内衬等添加物对金属陶瓷内衬显微硬度和耐蚀性的影响。研究结果表明:当加入稀土La2O3和SiO2时均可使陶瓷层内衬的孔隙率降低,当La2O3和SiO2的加入量分别为0.5%和2.0%时,对陶瓷层性能的提高效果最好,使孔隙率降低至3%,耐蚀性达到0.06g/m2·h,在一定程度上使陶瓷内衬的耐蚀性增加,La2O3对提高陶瓷层性能的效果较好。     

Effect of Mo addition mode on the microstructure and mechanical properties of TiC–high Mn steel cermets

In TiC- and Ti(C,N)-based cermets, the wettability of the ceramic phase with the metallic binder is commonly increased through supplementation with Mo in the form of pure Mo powder or Mo₂C. Herein, TiC–high Mn steel cermets were fabricated by conventional powder metallurgy techniques using Fe–Mo pre-alloyed powders as binders to guarantee uniform Mo distribution, and the cermet preparation process was optimized and investigated in detail. The microstructures of the thus obtained cermets were observed by scanning electron microscopy and compared to those of a Mo-free cermet and a cermet prepared using pure Mo powder. The grain size of Fe–Mo powder cermets exceeded that of the Mo-free cermet but was much smaller and more homogeneous than that of the Mo powder cermet. For Fe–Mo powder cermets, angular and tetragonal TiC particles were observed at Mo contents of <1.2 wt%, while round shapes became dominant at higher Mo contents. The hardness of Fe–Mo powder cermets increased with increasing Mo content, as did transverse rupture strength, which was maximal (2264 MPa) at a Mo content of 2.4 wt%, while impact toughness was maximal (11.2 J/cm²) at a Mo content of 1.2 wt%. The above values exceeded those reported for similar conventional cermets, and the use of Fe–Mo pre-alloyed powder as a metallic binder was therefore concluded to be an attractive strategy of increasing the strength and toughness of TiC–high Mn steel cermets.     

Wetting and corrosion of yttria stabilized zirconia by molten slags

We present first results of a study dealing with the corrosion of yttria stabilized zirconia ceramics by molten slags. Good wetting of a typical metallurgical slag as a pre-requisite for an effective chemical interaction of melt and zirconia was found. Both the dissolution of Zirconia and the leaching of the stabilizing agent into the molten slag are observed corrosion mechanisms. The latter induces a phase transformation from tetragonal or cubic zirconia into the monoclinic modification. The transformation with its increase in volume by app. 5% induces cracks. Those act to give new pathways for the corrosive media, accelerating corrosion. Crucibles from Y-PSZ have been used as samples in experiments with various slags. We also demonstrate the use of cathodoluminescence microscopy as a powerful mapping tool for zirconia phase differentiation which was verified by Raman and XRD measurements.     

镁锆砖和镁铬砖的抗RH炉渣侵蚀性对比

为取代RH炉用镁铬材料,以电熔镁砂为主原料,分别加入单斜锆、脱硅锆、单斜锆与脱硅锆的混合粉、锆英石制备了ZrO2质量分数分别为15%和20%的镁锆砖,并利用静态坩埚法对比研究了镁锆砖和镁铬砖的抗RH炉渣侵蚀性。结果表明:对于Al2O3含量高且碱度(CaO/SiO2比)大的RH炉渣,镁锆砖抗侵蚀性能优于镁铬砖的;镁锆砖的侵蚀机理是砖中的ZrO2与渣中的CaO迅速反应,形成高熔点物相CaZrO3,能堵塞砖中的孔隙而形成致密保护层,从而阻止钢渣对镁锆砖的进一步侵蚀;而镁铬砖的侵蚀机理是渣中的Al2O3、Fe2O3等R3 和镁铬尖晶石中Cr3 交换,渣与砖反应生成的镁铝尖晶石和镁铁尖晶石使得材料变性,同时由于体积效应使镁铬材料鼓胀开裂,从而导致镁铬砖的严重侵蚀。     

气化炉用后高铬砖的渣蚀机理

采用扫描电镜和XRD等分析方法,对石油焦气化炉和水煤浆气化炉用后高铬砖及渣蚀试验砖的显微结构进行了观察与分析。根据高铬砖显微结构变化,研究了在不同气化炉内高铬砖受熔渣侵蚀损毁的机理。结果表明:石油焦气化炉用高铬砖中的Cr2O3与熔渣中的V2O5接触反应,在低温下形成液相而被熔蚀,是其蚀损的主要原因;水煤浆气化炉用高铬砖蚀损的主要原因是Cr2O3在熔渣里的溶解和ZrO2的熔蚀;LIRR-HK95砖由于成分和结构的优化,抗石油焦渣侵蚀性能好。     

含钒渣对铝碳材料的侵蚀

为了探讨含矾渣对铝碳材料的侵蚀机制,用动态感应抗渣法研究了w(V2O5)=10%、碱度2.8,w(V2O5)=6%、碱度2.8,w(V2O5)=6%、碱度1.44的3种含钒渣对铝碳材料的侵蚀。结果表明:随着V2O5含量(w)由6%增加到10%,铝碳材料的熔损指数增加;随着碱度的增加,铝碳材料的熔损指数也增加;添加电熔镁砂有助于提高铝碳材料的抗侵蚀性能。显微分析表明:V、Ti元素渗透能力强,渗透深,而尖晶石可固溶少量V2O5、MnO及FeO。     

Al_2O_3－SiC－C质浇注料抗热震性和抗渣铁侵蚀性的研究

对新研制的Ａｌ２Ｏ３－ＳｉＣ－Ｃ质浇注料和现用出铁沟料的抗热震性和抗渣铁侵蚀性进行了研究、结果表明，该材料具有较高的抗渣铁侵蚀能力和较好的抗热震稳定性。调节Ｓｉ与Ｃ的比例可生成高强度、耐渣蚀的纤维状ＳｉＣ。     

Evolution of microstructure and interfacial characteristics of complete solid-solution Ti(C,N)-based cermets fabricated by mechanical activation and subsequent in situ carbothermal reduction

Complete solid-solution Ti(C,N)-based cermet, with no typical core-rim structure, was synthesized through mechanical activation and subsequent in situ carbothermal reduction method. XRD, SEM, TEM, and C/N analysis were used to investigate the microstructure, phase transformation, and the interfacial characteristics of the present cermets. During solid-state sintering, the (Ti,Mo)C/(Ti,Mo)(C,N) phases formed through the transformation of Mo-based solid solution which generated by mechanical activation. Then, the formed (Ti,Mo)C/(Ti,Mo)(C,N) continuously dissolved into the nickel-based binder above 1100 °C. It was found that in the subsequent stage of liquid sintering, the mechanical activation and also the presence of extremely fine TiC/Ti(C,N) particles accelerated the Mo diffusion into the hard phase, resulting in a large quantity of (Ti,Mo)(C,N) solid solutions formed in the nickel-based binder. Finally, complete (Ti,Mo)(C,N) solid-solution phase was obtained via dissolution and re-precipitation. The higher toughness and transverse rupture strength (TRS) of the synthesized new cermet, as compared with traditional cermets, were mainly caused by the increased crack deflection and transgranular fracture of the novel cermets. Moreover, the interface among the Ni-based binder phase and complete solid solution hard phase exhibited a semi-coherency state with high-density dislocations, which also significantly improved the TRS and toughness of the synthesized cermets.     

新型Ti(C,N)基金属陶瓷刀具的磨损性能

金属陶瓷由于具有优良的综合性能而广泛用作刀具材料.本文研究了纳米TiN改性TiC基金属陶瓷刀具的组织及其在加工正火态45号钢时的磨损性能.结果表明,与传统金属陶瓷相比,新型金属陶瓷的组织更细小.与传统金属陶瓷刀具、Al2O3刀具及YT15硬质合金刀具相比,新型金属陶瓷刀具具有更高的刀具寿命和切削效率,且主要以"磨损"形式失效.     

Study on Microstructure and Slag Corrosion Mechanism of High Chrome Bricks for Gasifier

1 Introduction The gasifier like Texaco style is of important tech- nical equipment for ammonia synthesis and production of carbamide, carbinol and ethylene etc. Due to differ- ent energy resource structure, petroleum coke is adopt- ed as rawmaterial in A…